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Help/Advice needed. Can not focus my C9.25 edge to pinpoint

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#1 MidniteCowboy



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Posted 19 September 2020 - 03:18 PM

So trying to get good view of the 3 planets up there right now with my C9.25 Edge HD. Jupiter kind of blobby. Moons not pinpoint.  Looked at Deneb to focus and could not bring pinpoint focus in.  Collimation looks a little off but hard to measure when central star wont focus.


I loaded C9.25 on mount three nites ago. Prior to that it was too smoky here to do any viewing.  I think something may have happened during taking off, down time and reload time.  When I first slewed to Jupiter the focus went out as if something had shifted.  That didnt happen again but ... it had never happened before.


I can only think of pulling the corrector plate off to see if the secondary has come loose or something.  Does anyone have other ideas or advice?



#2 Jim Waters

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Posted 19 September 2020 - 03:25 PM

I wouldn't do anything to the scope other than collimation until the smoke clears.  You can collimate the scope with smoke in the air.  Your issues are likely smoke related.



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#3 Xtatic


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Posted 30 September 2020 - 07:22 PM

While I am a complete noobie, I had this issue a few nights ago on my 8" evo HD.  Only thing I could focus sharp was the moon.  It turns out it was simply a bad seeing night, and the following night it had improved greatly.  

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#4 gnowellsct



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Posted 05 October 2020 - 03:31 PM

When the sky is bad, you can still collimate


(link to Astromart instructions)

#5 Eddgie



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Posted 05 October 2020 - 04:12 PM

Xtatic Has given the best response here.  


If you look at a planet or a star at high power and you detects any movement in the patter of the star, or any disturbance around the edge of a moon, then this is a function of atmospheric disturbance or boundary layer currents on your mirror (thermal equilibration not reached) or a combination of both.  


I am not saying that your collimation might not be out because maybe it is, but miscollimation does not cause the image to bubble and dance.  Even if the scope is in perfect collimation, the light refracting through the air currents in the atmosphere or in the boundary layer in front of the mirror will greatly affect the image quality.


If you look at a star at 200x and you see any kind of motion in the pattern of the star, like bubbling or flaring then your scope will not perform at its maximum potential and if the seeing is so poor that you can't even see a semblance of a first diffraction ring on a bright star then collimation is not to going to change that.  The image will be bad whether the scope is in perfect collimation or not.  In a 9" scope, seeing and thermals will almost always degrade the image.  How much is a function of how bad the conditions are. 

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